Blog on AF performance of K7

lithos · 03-19-2010, 07:29 AM

Originally posted by Samsungian

And within a decade Canon dominated autofocus most likely due to starting off with a new & larger diameter mount. Ring motors instead of micro motors in lenses.

You want to know how Canon really dominated AF?

Two words: Loss. Leader.

kari · 03-19-2010, 07:56 AM

Originally posted by alunfoto

But first I'll have to improve my finances after the trip to Antarctica. That one certainly didn't come free! But I'd do it again if I could. Worth every penny and more.

I get paid to go there! I'm leaving for Marion Island (subantarctic island) for 14 months in 2 weeks' time.

user440 · 03-19-2010, 08:16 AM

Originally posted by alunfoto

.... By complaining, you do something to your own expectations that will influence your photography also.

I understand what you're saying here, but the technology is in itself influencing my photography. When I want to go out to expand my race car photography, I have a inherent disadvantage over the guy next to me. I have to work a lot harder to get the good shot. It can be done of course, I have hundreds of pictures to prove it. Can it be done as easy, with as little effort, and with a greater ratio of keepers as the guy with the 50D next to me? No.

alunfoto · 03-19-2010, 08:40 AM

Originally posted by gazonk

About the sensor types: I don't think you're quite right about this. According to my K10D manual, all central 9 sensors are "wide cross area sensors" - only the two border sensors are not.

Hmm... I didn't know that.
My assumption was simply based on how much hunting the central sensor does, compared to the other sensors. There's got to be some kind of tech difference between the centre sensor and the other eight in the rectangle...

K7er · 03-19-2010, 08:46 AM

Originally posted by luke0622

I messed with 7D and D300s at local Best Buy stores, it seems K-7 definitely has a little better AF than the competitions

I first bought my K7 (with kit lenses) and then after a few months was messing with a few Canon's at the store. Of-course, they were big and unwieldy. I look through the view finder and half-press the shutter -- focus looked good. I point it far away, do the half-press again -- no change. Hmm, I ponder what's going on -- I keep iterating (point, half-press), everything seemed to be in focus always. Then it struck me, that the autofocus was actually locking so fast and silent with a USM lens

. However, I will note that I can't speak for better how better the SDM lenses on a K7 would do.

alunfoto · 03-19-2010, 08:58 AM

Originally posted by Samsungian

Actually Pentax & Minolta were 1st to offer autofocus, if I recall correctly.

Well yes, if you count the ME-F with that one-off oddball zoom, Pentax was actually first to introduce AF.

Minolta's Dynax (alpha/Maxxum) 7000 came in 1985. The first screwdrive AF camera from Pentax (SFX) came in 1987, same year as the first Canon EOS (650). The SFX was lagging behind already then, IIRC. The Z-1 did some good to catch up, but the other brands raised the notch ahead of Pentax all the time.

But hey, this is just wikipedia stuff... There is a practical difference between "best" and "good enough". I'd say Pentax is firmly with the latter now.

alunfoto · 03-19-2010, 09:06 AM

Originally posted by kari

I get paid to go there! I'm leaving for Marion Island (subantarctic island) for 14 months in 2 weeks' time.

Agh!

Some folks have all the luck. But wait...

14 months?

Still, I'm envious. Experience for life!

gazonk · 03-19-2010, 09:13 AM

Originally posted by alunfoto

Hmm... I didn't know that.
My assumption was simply based on how much hunting the central sensor does, compared to the other sensors. There's got to be some kind of tech difference between the centre sensor and the other eight in the rectangle...

I haven't really experienced any difference - but maybe it depends on the lens? Or maybe (even if it's not specified as such) the centre sensor has higher light sensitivity as in similar cameras from other brands? One would think that they would specify that, though...

Nass · 03-19-2010, 09:15 AM

Jostein, Just a comment from another k-7 user - thanks. What really shines through in your blog is your ability to understand why the equipment does what it does and how to get the most out of it. That's what seperates the men from the boys in my book =)

Urkeldaedalus · 03-19-2010, 10:42 AM

I think people who complain about the K-7 autofocus performance quite often do not own K-7s.

I do hope they continue the improvements with the next camera to further narrow the gap between the best performance offered by Nikon and Canon. However, I think there will be a point eventually where if the performance is good enough for getting a photo, does it really matter if Pentax is not exactly as good as the best out there? The K-7 is pretty close to this right now.

One of the things I liked about your blog entry is in a lot of the situations you kept fighting to get a shot when things didn't work out right away. Although these situations can be frustrating, when the day comes when auto focus can handle every situation with absolute ease, it will be the day when the camera takes the photo instead of the photographer.

GoremanX · 03-19-2010, 11:41 AM

Originally posted by Urkeldaedalus

I do hope they continue the improvements with the next camera to further narrow the gap between the best performance offered by Nikon and Canon. However, I think there will be a point eventually where if the performance is good enough for getting a photo, does it really matter if Pentax is not exactly as good as the best out there? The K-7 is pretty close to this right now.

This will always be dependant on the user's needs more than anything else. For my needs, the K-7's autofocus performance is more than adequate. For a sports photographer, not so much. But Pentax doesn't really cater to the sports photographer. If and when they do, I'm sure autofocus will be one of the first things they address.

K7er · 03-19-2010, 12:10 PM

The question I would ask is whether their AF "algorithms" are not up-to-mark or it is just a matter of pure processing power, i.e., this can also include light paths, beam splitting. If it's the latter; that where's the reduced price for the cameras kick in.

CWyatt · 03-19-2010, 01:06 PM

K-7 does certainly not have faster AF than D300S or 7D. However, it is pretty good. And significantly smaller and cheaper, and better is other areas.

Originally posted by alunfoto

@ CWyatt:
"they" is just me, I'm afraid. Noone to hide behind. The reason I use AlunFoto as sort of a pseudonym is that I live close by a lake called Alunsjøen.

As to your question about autofocus type, I can elucidate:
For birds in flight, continuous mode is the only alternative, really. In particular if you want to rattle off exposure series in hope of catching particularly significant moments.

Further, I found that using the centre sensor gives the best AF result. Even if you have to crop afterwards to get a good composition. The lateral sensors are not of crosshair type, and so tend to miss if the contrast lines in the motif aligns with the sensor. My experience from the Antarctica trip is that using all sensors slows the AF down. I tried all variants over the course of the trip, both matrix, select and single.

Incidentally, this was in line with the recommendation from the pros on board too. Canon ambassador and photographer Ole Jørgen Liodden (Velkommen til Naturfokus), held courses on board and insisted that for all Canon models, the centre sensor was always the best for tracking-AF. He just made a small reservation with regards to the new 7D, which can couple 5 sensors into a sort of giant crosshair (centre sensor + 4 adjacent), apparently without any AF speed penalty. But the centre sensor is still involved.

Hope this answers your questions.

Thanks for that. Interesting. I never use anything much other than centre point for speed and accuracy, but then I don't shoot much nature so I don't know what people were using there with the K-7.

**Pål Jensen** · 03-19-2010, 01:13 PM

Originally posted by K7er

The question I would ask is whether their AF "algorithms" are not up-to-mark or it is just a matter of pure processing power, i.e., this can also include light paths, beam splitting. If it's the latter; that where's the reduced price for the cameras kick in.

I think it mostly in the head of some users. Frankly, almost all AF SLR's from the last 20 years are fast enough to focus on almost anything the photgrapher can point it at. It just that some are annoyed that other brands of cameras are faster at spinning the lens through the helicoid with the lens cap on.

**StigVidar** · 03-19-2010, 02:27 PM

Even my old *istDS had no problem at all focusing a F1 car at 200-250km/t from a distance of about 30 meters. The lens used was a FA400/5,6. In fact, most shots that day was perfectly in focus. They passed this turn so fast that I struggled with pointing the camera at them.

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03-19-2010, 07:29 AM	#16
lithos Inactive Account Join Date: Oct 2007 Location: Brisbane, QLD, AUS Posts: 3,261	Originally posted by Samsungian And within a decade Canon dominated autofocus most likely due to starting off with a new & larger diameter mount. Ring motors instead of micro motors in lenses. You want to know how Canon really dominated AF? Two words: Loss. Leader.

03-19-2010, 07:56 AM	#17
kari Senior Member Join Date: Feb 2010 Photos: Albums Posts: 142	Originally posted by alunfoto But first I'll have to improve my finances after the trip to Antarctica. That one certainly didn't come free! But I'd do it again if I could. Worth every penny and more. I get paid to go there! I'm leaving for Marion Island (subantarctic island) for 14 months in 2 weeks' time.

03-19-2010, 08:16 AM	#18
user440 Veteran Member Join Date: Jan 2007 Location: St. Louis, MO Photos: Gallery Posts: 349	Originally posted by alunfoto .... By complaining, you do something to your own expectations that will influence your photography also. I understand what you're saying here, but the technology is in itself influencing my photography. When I want to go out to expand my race car photography, I have a inherent disadvantage over the guy next to me. I have to work a lot harder to get the good shot. It can be done of course, I have hundreds of pictures to prove it. Can it be done as easy, with as little effort, and with a greater ratio of keepers as the guy with the 50D next to me? No.

03-19-2010, 08:40 AM	#19
alunfoto Forum Member Join Date: Apr 2008 Location: Norway Photos: Gallery Posts: 72	Originally posted by gazonk About the sensor types: I don't think you're quite right about this. According to my K10D manual, all central 9 sensors are "wide cross area sensors" - only the two border sensors are not. Hmm... I didn't know that. My assumption was simply based on how much hunting the central sensor does, compared to the other sensors. There's got to be some kind of tech difference between the centre sensor and the other eight in the rectangle...

03-19-2010, 08:46 AM	#20
K7er Forum Member Join Date: Dec 2009 Posts: 58	Originally posted by luke0622 I messed with 7D and D300s at local Best Buy stores, it seems K-7 definitely has a little better AF than the competitions I first bought my K7 (with kit lenses) and then after a few months was messing with a few Canon's at the store. Of-course, they were big and unwieldy. I look through the view finder and half-press the shutter -- focus looked good. I point it far away, do the half-press again -- no change. Hmm, I ponder what's going on -- I keep iterating (point, half-press), everything seemed to be in focus always. Then it struck me, that the autofocus was actually locking so fast and silent with a USM lens . However, I will note that I can't speak for better how better the SDM lenses on a K7 would do.

03-19-2010, 08:58 AM	#21
alunfoto Forum Member Join Date: Apr 2008 Location: Norway Photos: Gallery Posts: 72	Originally posted by Samsungian Actually Pentax & Minolta were 1st to offer autofocus, if I recall correctly. Well yes, if you count the ME-F with that one-off oddball zoom, Pentax was actually first to introduce AF. Minolta's Dynax (alpha/Maxxum) 7000 came in 1985. The first screwdrive AF camera from Pentax (SFX) came in 1987, same year as the first Canon EOS (650). The SFX was lagging behind already then, IIRC. The Z-1 did some good to catch up, but the other brands raised the notch ahead of Pentax all the time. But hey, this is just wikipedia stuff... There is a practical difference between "best" and "good enough". I'd say Pentax is firmly with the latter now.

03-19-2010, 09:06 AM	#22
alunfoto Forum Member Join Date: Apr 2008 Location: Norway Photos: Gallery Posts: 72	Originally posted by kari I get paid to go there! I'm leaving for Marion Island (subantarctic island) for 14 months in 2 weeks' time. Agh! Some folks have all the luck. But wait... 14 months? Still, I'm envious. Experience for life!

03-19-2010, 09:13 AM	#23
gazonk Pentaxian Join Date: Feb 2009 Location: Oslo area, Norway Photos: Gallery \| Albums Posts: 3,746	Originally posted by alunfoto Hmm... I didn't know that. My assumption was simply based on how much hunting the central sensor does, compared to the other sensors. There's got to be some kind of tech difference between the centre sensor and the other eight in the rectangle... I haven't really experienced any difference - but maybe it depends on the lens? Or maybe (even if it's not specified as such) the centre sensor has higher light sensitivity as in similar cameras from other brands? One would think that they would specify that, though...

03-19-2010, 09:15 AM	#24
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402	Jostein, Just a comment from another k-7 user - thanks. What really shines through in your blog is your ability to understand why the equipment does what it does and how to get the most out of it. That's what seperates the men from the boys in my book =)

03-19-2010, 10:42 AM	#25
Urkeldaedalus Veteran Member Join Date: Dec 2008 Location: Iowa Photos: Gallery \| Albums Posts: 1,369	I think people who complain about the K-7 autofocus performance quite often do not own K-7s. I do hope they continue the improvements with the next camera to further narrow the gap between the best performance offered by Nikon and Canon. However, I think there will be a point eventually where if the performance is good enough for getting a photo, does it really matter if Pentax is not exactly as good as the best out there? The K-7 is pretty close to this right now. One of the things I liked about your blog entry is in a lot of the situations you kept fighting to get a shot when things didn't work out right away. Although these situations can be frustrating, when the day comes when auto focus can handle every situation with absolute ease, it will be the day when the camera takes the photo instead of the photographer.

03-19-2010, 11:41 AM	#26
GoremanX Veteran Member Join Date: Dec 2009 Location: Georgia, VT Photos: Albums Posts: 1,657	Originally posted by Urkeldaedalus I do hope they continue the improvements with the next camera to further narrow the gap between the best performance offered by Nikon and Canon. However, I think there will be a point eventually where if the performance is good enough for getting a photo, does it really matter if Pentax is not exactly as good as the best out there? The K-7 is pretty close to this right now. This will always be dependant on the user's needs more than anything else. For my needs, the K-7's autofocus performance is more than adequate. For a sports photographer, not so much. But Pentax doesn't really cater to the sports photographer. If and when they do, I'm sure autofocus will be one of the first things they address.

03-19-2010, 12:10 PM	#27
K7er Forum Member Join Date: Dec 2009 Posts: 58	The question I would ask is whether their AF "algorithms" are not up-to-mark or it is just a matter of pure processing power, i.e., this can also include light paths, beam splitting. If it's the latter; that where's the reduced price for the cameras kick in.

03-19-2010, 01:06 PM	#28
CWyatt Veteran Member Join Date: Jul 2009 Posts: 1,291	K-7 does certainly not have faster AF than D300S or 7D. However, it is pretty good. And significantly smaller and cheaper, and better is other areas. Originally posted by alunfoto @ CWyatt: "they" is just me, I'm afraid. Noone to hide behind. The reason I use AlunFoto as sort of a pseudonym is that I live close by a lake called Alunsjøen. As to your question about autofocus type, I can elucidate: For birds in flight, continuous mode is the only alternative, really. In particular if you want to rattle off exposure series in hope of catching particularly significant moments. Further, I found that using the centre sensor gives the best AF result. Even if you have to crop afterwards to get a good composition. The lateral sensors are not of crosshair type, and so tend to miss if the contrast lines in the motif aligns with the sensor. My experience from the Antarctica trip is that using all sensors slows the AF down. I tried all variants over the course of the trip, both matrix, select and single. Incidentally, this was in line with the recommendation from the pros on board too. Canon ambassador and photographer Ole Jørgen Liodden (Velkommen til Naturfokus), held courses on board and insisted that for all Canon models, the centre sensor was always the best for tracking-AF. He just made a small reservation with regards to the new 7D, which can couple 5 sensors into a sort of giant crosshair (centre sensor + 4 adjacent), apparently without any AF speed penalty. But the centre sensor is still involved. Hope this answers your questions. Thanks for that. Interesting. I never use anything much other than centre point for speed and accuracy, but then I don't shoot much nature so I don't know what people were using there with the K-7.

03-19-2010, 01:13 PM	#29
Pål Jensen Site Supporter Join Date: Dec 2007 Location: Norway Photos: Albums Posts: 4,371	Originally posted by K7er The question I would ask is whether their AF "algorithms" are not up-to-mark or it is just a matter of pure processing power, i.e., this can also include light paths, beam splitting. If it's the latter; that where's the reduced price for the cameras kick in. I think it mostly in the head of some users. Frankly, almost all AF SLR's from the last 20 years are fast enough to focus on almost anything the photgrapher can point it at. It just that some are annoyed that other brands of cameras are faster at spinning the lens through the helicoid with the lens cap on.

03-19-2010, 02:27 PM	#30
StigVidar Site Supporter Join Date: Nov 2006 Location: Norway Photos: Gallery \| Albums Posts: 705	Even my old *istDS had no problem at all focusing a F1 car at 200-250km/t from a distance of about 30 meters. The lens used was a FA400/5,6. In fact, most shots that day was perfectly in focus. They passed this turn so fast that I struggled with pointing the camera at them.